Wall cake cutter



May 2, 1961 E. R. SEWARD ET AL 2,982,359

WALL CAKE CUTTER 2 Sheets-Sheet 1 Fig.2. 4

Filed Oct. 15, 1956 t/&\

E. R. SEWARD ET AL 2,982,359

May 2., 1961 WALL CAKE CUTTER 2 Sheets-Sheet 2 Filed Oct. 15, 1956 a l H "a.

lllllllrli and gelled mud mented.

2,982,359 1* WALL HCU I R 1 r Edwin R. Seward .and Williarnb. Gainer, -New Orleans,

.Lfla, assignors toASCO Autoniatic Specialties. Corpo- T i a New Or e ns, La 21 corporationgofLouisianag' Film; 1 a set. No ans.

1 2 Claims. or. 1.66-1--175) The invention relates to ,deviees used in drilling wells and is particularly directed to, improvements in cleanmg and surface finishing devices-for removing filter cake from sections of wlell bores to be ce his a principal object oftheinvention 'tojjprovide i -pnot by a scraping but by a cutting action.-

It is a further object of the invention to provide a .well scratcher which covers the full bore ofthe Well hole with onestroke. x l 7 Another object of the invention is to provide a well scratcher which can readily be placed inposition on the casing'and permanently locked thereto, .withontrsubstan- ,tially slowing down the operation.

. ,Otherbbjects and advantages will beconiei appar ent from a consideration of the'specification and; claims. 1

According, to our invention, the cutting elements are formed asthin strips or blades of spring mate -n11 fixed with their inner ends to the body of a sleeve or collar by riveting, screwing or welding, while their freeoutene nds calledwellscratcher, which lpr o'rms thejeleaning effect atented May 2, last axial directions. We provide manually controllable means for keepingfthe locking membersin inactive positionin theirrecesses while the carrier is positioned on the casing, and for releasing the locking members to activate the coupling. Ina preferredembodiment of our'invention, said control means are wires threaded throughcircularly arranged internal guide holes of the carrier sleeve and aligned holes of the locking members, the wires being provided with protruding loops to pull'them out of theirvhojles forv releasing the locking members.

. Thelocking members of the couplingare, for instance, wedge-likebodies corresponding to the wedge like shape of the recesses in the carrier sleeve, whereby .the inner surfaces of these wedge-like bodies contacting'thecasing are preferably provided with ratchet teeth to increase the locking effect. i l.

' Sp'ring means are providedin the enlarged portions of the recesses and force the locking members, after they have been,-r eleased, into locking position Said spring n leans may be rubber blocks, abutting, with their inner faces, the bases at the twin sets of the lockingmembers.

I In the I accompanying drawing;- 7

,.i r 1gin;elevation an inserted casing string, and, attached to it,..a mud cutting device according to the invention;

2 is anenlarged elevation of themud cutting device;

.Fig. 3 a plan view ofthis device at the sarne scale .-,Fig.' 4, shows in.,vertical section the carrier sleeve for J a "the cutting blades with the coupling means and' nanually lie on a circle of a diameter substantially eguakto the-r;

diameter of' the well bore. Said bladesare curved from their fixedto their free endsin circumferential, outward, and upward direction, so that the blades lie on the sun face of an imaginary conic f-rustrum; the lowercirole. of

' i which coincides with the circle of the fixed blade ends,

while its upper circle, substantially of the diameter of the well bore, coincides with the'circle going through the free ends of the blades. By this formation, the blades are resilient and ofier only slight resistance, by bending inwardly, to the downward movement of the casing, thus performing a centering function only, while being more rigid in the opposite direction, thus performing effectively and uniformly the desired cutting action during one upward stroke of the casing string. Near their fixed ends, the blades are provided with open loops by coiling or twisting them, so as to form a narrow winding.

This increases the deflectibility of the blades and diminishes the working stresses, especially during the cutting stroke.

A sleeve-like carrier of the "blades is provided with internal couplingvmeans held in inactive position by releasable locking means for-freely shifting this carrier along casing string. The coupling means are formed as a set ber's released and inactivated position;

40 a A v I p .'-,rnent; of the coupling means of the blade carrying sleeve.

j c ontrollablemeans in'inac'tive position; Fig. 5 .shows, partly in section, thelockingmembers' of the coupling'ininactive position; N

Fig. 6isa; similar section showing the locking mem- ,,Figl 7::is a perspective view of one of the locking members;

vertical section' showing another ernbodi- Iri Fig. '1, 10 represents the bore of thewell, in which a casing string 11 is inserted. Onthis casing string, a sleeve-like carrier 12 is arranged, equipped with a series of circularly evenly spaced'cutting blades 13, the free outer ends of which cut into the layer or cake of mud 14 covering the genuine strata of the bore wall and shave same 01f uniformly all around the wall in a single short upward stroke of the casing string. 'If'required, several such carriers may be employed.

As illustrated in Figs. 2 and 3, the cutting blades 13 are formed as thin fiat strips of sprlng'matcrial, which strips have in cross section alength of greater dimension i then the thickness; their inner ends 15 are riveted or otherwise fixed tofthe upper rim'16 of the carrier sleeve or collar 12 in uniform spacing so that the greater dimension lies tangentially against said collar in a plane generally parallel to the axis of the collarto provide of internal recesses in the collar or carrier with inclined rear walls cooperating with a set of locking members freely movable in these recesses and being forced, by a slight relative movement, into the narrowing gap between the carrier and the surface of the casing; preferablythe coupling means forms a twin set of internal recesses in the sleeve-like carrier with oppositely inclined rear walls co-operating' with locking members fereely movable axially in these recesses "to provide a rigid connection between casing and carrier in both:

stilfness against deflection upon upward movement of the collar. Near these inner ends, the blades 13 are provided with open loops 17, formed by twisting or coiling the strips. Then the strips forming the blades 13 are bent circumferentially and outwardly as well as upwardly 'in a generally helical form, so that their outer freeends are confined by a circle substantially of the diameter of the well bore. Due to this shape and manner of attachment, the blades are deflected inwardly and upwardly withslightresistance when the casing string is being lowered into the well bore,and hold the casing string in accurate alignment with the'bore. But when thecasing string is being moved upwardly, the blades tend to bend outwardly and downwardly with considerable resistance and cut into the layers of mud, shaving the wall of the well bore effectively and uniformly in a single upward stroke of the casing string.

For both these actions, it is necessary to hold the sleeve-like blade carrier 12 in rigid connection with the casing string. This is effected by special coupling means inside the carrier sleeve, which can be instantaneously brought into locked position where they allow the free The bases 25, 26, of wedges 19, 20, are abutted against :springs, preferably rubber blocks 27, arranged in the enlarged middle portion 28 of recesses 21, 22. v When springs 27 are held compressed and the wedge-like members are held abutted against them, no coupling between carrier sleeve 12 and casing 11 is efiected. But when spring 27 is released as well as members 19, 20, which then may slide in their recesses 21, 22, the rigid coupling is performed automatically.

To serve as controlling means for wedges 19, 20, and simultaneously for springs 27, wires 29, 30 are threaded through holes 31, 32, in wedges 19, 20, and aligned guide holes 33, 34, provided in the sidewalls of recesses 21, 22. In this position of the wires 29, 30, the wedges 19, 20, and compressed springs 27 are held inactive. But when the wires 29, 30 are pulled out, which can easily and rapidly be done by means of protruding loops 35, 36, the coupling means is released and slips into coupling position. Figs. and 6 show, respectively, the two positions of the coupling.

In the embodiment shown in Fig. 8, one'set only of locking members, formed as balls or rollers 40, is arranged in a corresponding set of symmetrically tapered recesses 41. When these balls or rollers 40 are held in the wider middle portion 42 of their recesses, they do not contact the outer surface of easing string 11 and are therefore inactive. But when freed, they enter into coupling position in both the downward and upward movement of the casing string. The controlling means for members 40 is again a wire 43, preferably provided with an external loop and threaded through holes of members 40 and'aligned holes inside carrier sleeve 12.

We claim:

1. A cleaning assembly for well bores comprising a collar rigidly connectable to a string of a casing to be inserted into the bore of a well, and a set of spaced resilient cutting blades fastened to the collar, said blades being fiat spring strips curvedupwardly and outwardly in a generally helical form, and having in cross-section a length of greater dimension than the thickness, said strips being attached to said collar so that the greater dimension lies tangentially against the collar to provide stifiness against deflection upon upward movement of the collar. 2. A wall cleaner as defined in claim 1, in which the strips forming the cutting blades are provided near their futed ends with open loops of relatively small diameter, the strip portions entering said loops from the fastening point of the blades being approximately tangent to the outer surface of said carrier, the strip portions leaving said loops having approximately the same angle of tang'ency, said angle of tang'ency being adjustable to adjust the average diameter of the surface of said imaginary conical frustrum.

References Cited in the file of this patent UNITED STATES PATENTS Yeargan Nov, 5, 1957 

